The proposed study is an investigation of the intracellular location of the enzymes involved in the transformation of adenosine nucleotides in the heart muscle and the physiological singificance of their distribution pattern. The enzymes to be studied are creatine kinase, adenylate kinase and adenylate deaminase and their interaction with myofibrils and other organelles. The bound enzymes will be characterized by biochemical and immunochemical techniques. Studies will also be conducted to see if the enzymatic behavior of the enzymes are altered as a result of such interaction.